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Biomedical subjects

S Oya

Publications and source records attributed to S Oya.

At least 19 recordsLinked to original sources
PubMed2006

Early administration of methylprednisolone decreases apoptotic cell death after spinal cord injury.

The purpose of this study is to evaluate, in an experimental model of spinal cord injury (SCI), the presence of apoptotic cell death after trauma and if early administration of a single bolus of methylprednisolone (MP) influences apoptosis in the zone of trauma and in adjacent spinal cord segments. For this study, a total of 96 adult female Wistar rats were subjected to spinal contusion at the T6-T8 level, producing immediate paraplegia. Forty-eight animals (treated group) received a single intraperitoneal injection of MP, at a dose of 30 mg/kg body weight, 10 minutes later. Cells undergoing apoptosis were detected by means of immunohistochemical labeling with the monoclonal antibody Apostain (anti-ssDNA MAb F7-26), in the injured spinal cord tissue, both in the zone of the lesion and in the adjacent spinal segments (rostral and caudal zones), 1, 4, 8, 24 and 72 hours and 1 week after injury. Apoptosis was detected in neurons and glial cells in the zone of the lesion 1 hour after trauma, with a pattern that showed no changes 4 hours later. Between 4 and 8 hours postinjury, the number of apoptotic cells increased, after which it decreased over the following days. In the adjacent spinal segments, apoptotic cells were detected 4 hours after trauma, and increased progressively over the remainder of the study, the number of apoptotic cells being similar in the lesion zone and in rostral and caudal zones one week after injury. When the group of MP-treated animals was considered, significant decreases in the number of apoptotic cells were detected in the lesion zone 24 hours after injury, and in the rostral and caudal zones, at 72 hours and at 1 week after trauma. These findings show that early administration of a single bolus of MP decreases apoptotic cell death after SCI, supporting the utility of MP in reducing secondary damage in injured spinal cord tissue.

Animals↗
PubMed2004

Diffusion property following functional hemispherectomy in hemimegalencephaly.

Diffusion-tensor imaging (DTI), a unique magnetic resonance technique for analysis of diffusion-anisotropy of the brain, can identify subtle white matter changes in vivo. To investigate changes of truncated neurofibers, DTI was conducted prior to and following functional hemispherectomy in a female infant for refractory epilepsy associated with hemimegalencephaly. Anisotropy of the amputated pyramidal tract decreased relative to the unaffected side after surgery, which reflects secondary degeneration in neurofibers. In DTI applied to infants, differentiation between developmental changes and changes associated with the current phenomenon must be evaluated cautiously. Standardization of diffusion-tensor analysis of developmental change is desirable.

Adult↗
PubMed2003

Near-infrared spectroscopy evaluated as a technique for estimating udder haemodynamics in the lactating cow.

Near-infrared spectroscopy (NIRS) that requires few compact instruments is a non-invasive and continuous method of monitoring haemodynamics in living organs. To assess the feasibility of using NIRS in evaluating the udder haemodynamics in six dairy cows, a probe component consisting of a light-emitting diode and a phototransistor was attached to the left side of the udder surface. Real-time variation of tissue haemodynamics was analysed and the data were transferred to the computer by way of a radiotelemetry system. On induction of temporary congestion by applying pressure with the hand pressed firmly against the left milk vein for 20 s, concentration of oxyhaemoglobin decreased throughout the 20-s duration of congestion, and concentration of deoxyhaemoglobin increased. A surge in blood volume was also observed from the beginning of congestion, then the volume attenuated to baseline. The data demonstrated that the reading seen on the monitor reflects the real-time status of the mammary gland. NIRS shows promise as a useful approach to physiological studies.

Animals↗
PubMed2002

Imbalance between apostain expression and proliferative index can predict survival in primary glioblastoma.

BACKGROUND: Cell proliferation and cell death are opposing processes in tumour growth, with tumour progression reflecting the balance between proliferating and apoptotic cells. The purpose of the present study is to verify the hypothesis that an imbalance between apoptosis and proliferation can predict survival in patients with primary glioblastoma. METHODS: After the immunohistochemical study of Apostain and MIB-1 expression, the index of apoptosis (AI), the index of proliferation (PI), and the ratio AI/PI was recorded for each tumour specimen, in a series of 32 primary glioblastomas. Studies of correlation between AI and PI, between AI and survival, between PI and survival, and between the ratio AI/PI and survival, were performed using the Spearman rank correlation test. Furthermore, a comparative study of survival was performed for subgroups of patients with ratio AI/PI greater or lesser than 1, using the log rank test. FINDINGS: In the present series, values of AI and PI showed a wide distribution, with a mean +/- SD of 8.16 +/- 7.2, and of 12.69 +/- 21.1, respectively. The values for the ratio AI/PI ranged between 0.01 and 6.03 (mean +/- SD: 1.44 +/- 1.60). Statistical study failed to obtain correlation between AI and PI. Survival of patients not correlated with AI neither with PI. The ratio between AI and PI did not correlate with survival either. Nevertheless, when survival for the subgroups of patients showing a ratio AI/PI greater or lesser than 1 was compared, a significant difference was found (p: 0.02). Survival ranged between 50 and 81 weeks (mean of 58.5 +/- 11.05 weeks) for the 12 cases showing a ratio AI/PI greater than 1, and it ranged between 8 and 85 weeks (mean: 38.20 +/- 25.37 weeks) for the 20 cases showing a ratio AI/PI lesser than 1. INTERPRETATION: Our present results suggest that a clear imbalance between cell proliferation and apoptosis can predict outcome in patients operated on for a primary glioblastoma.

Aged↗
PubMed2001

Expression and significance of vascular permeability factor in tumour infiltrating lymphocytes of brain metastases.

BACKGROUND: Recently, vasogenic edema has been related to the expression of vascular permeability factor (VPF) by tumour cells in brain metastases. On the other hand, expression of VPF has been reported in inflammatory cells. Keeping in mind the current presence of tumour-infiltrating lymphocytes (TIL) in brain metastases, our objective is to study the expression and significance of VPF in TIL-cells from specimens of brain metastases. METHOD: Tumour samples from 16 brain metastases associated with peritumoural edema were immunohistochemically studied for demonstration of VPF. The degree of VPF-expression by tumour cells and TIL was determined, and correlated with the degree of peritumoural edema. FINDINGS: Our present results show that, independently of the VPF-positivity expressed by the tumour cells, VPF-expression is a constant finding in TIL-cells of brain metastases, and correlated with the amount of peritumoural edema. INTERPRETATION: Our present findings suggest a role for TIL-cells in the development of vasogenic edema associated with brain metastases.

Brain Edema↗
PubMed2001

Functional recovery in chronic paraplegic rats after co-grafts of fetal brain and adult peripheral nerve tissue.

BACKGROUND: In recent years, experimental studies have sought some type of functional improvement in traumatic paraplegia by transplanting neural tissue into the injured spinal cord. The aim of this work is to study the possibility of functional recovery in chronic paraplegic rats after co-transplantation of fetal cerebral tissue and adult peripheral nerve tissue. METHODS: Seventy adult female Wistar rats were subjected to spinal cord injury at the T6-T8 level, causing complete paraplegia. Three months later, in 50 rats (grafted group) the injured spinal cord tissue received a graft of fetal brain cortex associated with crushed adult peripheral nerve. All the animals (grafted and control groups) were subjected to daily rehabilitation procedures from the first week after the injury, and evaluated weekly for motor and sensory recovery. Statistical analysis of different behavioral data between control and grafted animals was performed using the Kruskal-Wallis ANOVA and the nonparametric Wilcoxon test. RESULTS: Between 8 and 12 months after transplantation, progressive signs of functional recovery were observed in the grafted animals, associated with an increase in muscle mass in the lower extremities, findings that were significantly different from those in nongrafted animals (p < 0.05). At this time, donor cerebral tissue is integrated into previously injured spinal cord and results in formation of bundles of nerve fibers that emerge from the area of the transplant and surround the spinal cord beneath the lesion. CONCLUSIONS: Delayed co-transplantation of fetal cerebral tissue and peripheral nerve tissue can be used to achieve anatomical remodeling and long-term functional recovery in rats rendered paraplegic as result of severe spinal cord injury. These findings support the possibility of functional recovery after chronic traumatic paraplegia.

Analysis of Variance↗
PubMed2001

Delayed central respiratory dysfunction after Wallenberg's syndrome--case report.

A 68-year-old man presented with Wallenberg's syndrome consisting of ataxia, dysphagia, hypesthesia on the left side of the body, and Horner's syndrome on the right. Magnetic resonance (MR) imaging revealed a right lateral medullary infarction and small multiple lacunae scattered in the upper medulla. Neurological symptoms improved in a week and the patient was discharged with mild residual hypesthesia on the left side. However, 31 days later, he was emergently admitted after suddenly becoming apneic and losing consciousness. MR imaging detected no new lesion. The patient was placed under ventilation support for 48 hours before regaining normal respiratory function. Medullary infarction sometimes causes catastrophic respiratory failure, but Wallenberg's syndrome caused by lateral medullary infarction is rarely associated with central respiratory dysfunction, and delayed onset of central respiratory dysfunction is extremely unusual. Delayed onset of central respiratory failure is a life-threatening complication of the medullary infarction causing Wallenberg's syndrome, which in general is not recognized.

Aged↗
PubMed2001

Infra-posterior inferior cerebellar artery aneurysm arising after occlusion of the ipsilateral vertebral artery--case report.

An 85-year-old woman had subarachnoid hemorrhage due to rupture of a very rare left infra-posterior inferior cerebellar artery (PICA) aneurysm, a saccular aneurysm located proximally at the junction of vertebral artery (VA) and PICA. Right vertebral angiography demonstrated the aneurysm since the left VA was occluded in the extracranial portion. The aneurysm projected in the opposite direction to common VA-PICA aneurysms. The angiographical and intraoperative findings imply this rare aneurysm resulted from the hemodynamic changes caused by the VA occlusion. Detailed exploration of angiography is emphasized to detect such rare aneurysms among the diversity of hemodynamic patterns in elderly patients with subarachnoid hemorrhage.

Aged↗
PubMed2000

Selective in vitro and in vivo binding of [(125)I]ADAM to serotonin transporters in rat brain.

An improved iodinated tracer, ADAM (2-((2-((dimethylamino)methyl)- phenyl)thio)-5-iodophenylamine) for imaging serotonin transporters (SERT) with single photon emission computerized tomography (SPECT), was prepared and characterized. Scatchard analysis of saturation binding of [(125)I]ADAM to rat frontal cortical membrane homogenates gave a K(d) value of 0.15 +/- 0.03 nM and a B(max) value of 194 +/- 65 fmol/mg protein. Biodistribution of [(125)I]ADAM in rat brain after an iv injection showed a high specific binding in the regions of hypothalamus, cortex, striatum, and hippocampus, where SERT are concentrated and the specific binding peaked at 120-240 min postinjection [(hypothalamus-cerebellum)/cerebellum = 4.3 at 120 min post-iv injection]. Moreover, the specific hypothalamic uptake was blocked by pretreatment with SERT selective competing drugs, such as paroxetine and (+)McN5652, while other noncompeting drugs, such as ketanserin, raclopride, and methylphenidate, showed no effect. The radioactive material recovered from rat brain homogenates at 120 min after [(125)I]ADAM injection showed primarily the original compound (>90%), a good indication of in vivo stability in the brain tissues. Both male and female rats showed similar and comparable organ distribution pattern and regional brain uptakes. Ex vivo autoradiograms of rat brain sections (120 min after iv injection of [(125)I]ADAM) showed intense labeling in several regions (olfactory tubercle, lateral septal nucleus, hypothalamic and thalamic nuclei, globus pallidus, central gray, superior colliculus, substantia nigra, interpeduncular nucleus, dorsal and median raphes, and locus coerulus), which parallel known SERT density. These results strongly suggest that the novel tracer ADAM is superior to the congers (i.e., IDAM) reported previously. When labeled with I-123, ADAM will be an improved and useful SPECT imaging agent for SERT in the brain.

Animals↗
PubMed2000

Grafting of neural tissue in chronically injured spinal cord: influence of the donor tissue on regenerative activity.

BACKGROUND: To determine the influence of different nervous tissue grafts on the regenerative activity of chronically injured spinal cord, an experimental study examining the expression of the proliferating cell nuclear antigen (PCNA) in chronically injured spinal cord subjected to neural grafting was performed. METHODS: Three months after induced spinal cord injury, paraplegic Wistar rats were subjected to grafting of neural tissue. Grafts consisted of fetal brain cortex, fetal spinal cord, crushed adult peripheral nerve tissue, or fetal brain cortex combined with crushed adult peripheral nerve tissue. Four months later, the spinal cord was removed and the grafted zone was studied by means of immunohistochemical demonstration of PCNA. RESULTS: Different patterns of PCNA expression were recorded in the different experimental groups. PCNA-immunostained cells in injured spinal cord tissue, mainly ependymal cells and astrocytes, increased when co-transplantation of fetal brain cortex and crushed adult peripheral nerve tissue was used, in comparison to other neural donor tissues. In the grafted tissue, proliferative activity was greater when fetal brain cortex, alone or with peripheral nerve, was used, in comparison to the use of fetal spinal cord or adult peripheral nerve tissue. Nevertheless, the number of PCNA-positive cells does not seem to be influenced by the presence of peripheral nerve tissue in the donor tissue. CONCLUSIONS: Our present findings suggest the effectiveness of co-transplantation of peripheral nerve tissue and fetal brain tissue in attempts at spinal cord reconstruction after injury.

Animals↗
PubMed2000

Prognostic significance of clinical and angiogenesis-related factors in low-grade oligodendrogliomas.

BACKGROUND: Keeping in mind that oligodendrogliomas have unpredictable biological behavior, the aim of this study is to investigate the prognostic significance of VEGF expression and microvessel density in a homogeneous series of low-grade oligodendrogliomas. METHODS: For this study 36 patients with a low-grade oligodendroglioma treated by surgical resection and radiotherapy were selected. At the time of surgery, in all cases the Karnofsky Performance Scale (KPS) score was more than 70, and the study of the resected tumor disclosed a Ki-67/MIB-1 labeling index (MBI-1 LI) less than 1%. In this homogeneous series, immunohistochemical studies were performed using monoclonal antibodies against VEGF in order to study the expression of this cytokine, and against vascular endothelial CD-34 antigen, in order to identify microvessels. RESULTS: Our results show that in contrast to low-grade astrocytomas, low-grade oligodendrogliomas lacked immunoreactive VEGF. Oligodendrogliomas with low vascular density (less than 20 microvessels per microscopical field, at 200 x) or high vascular density (more than 100 microvessels per field, at 200 x) were identified, but this factor had no influence on the survival rate of patients. On the other hand, analysis of the present series showed that clinical factors, such as age or extent of surgical resection, were not significantly associated with survival. CONCLUSIONS: In contrast to low-grade astrocytomas, the angiogenesis score of low-grade oligodendrogliomas (counting the number of microvessels in tumor tissue) adds little information to help predict tumor behavior.

Antigens, CD34↗
PubMed2000

2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine (ADAM): an improved serotonin transporter ligand.

Serotonin transporters (SERT) are target-sites for commonly used antidepressants, such as fluoxetine, paroxetine, sertraline, and so on. Imaging of these sites in the living human brain may provide an important tool to evaluate the mechanisms of action as well as to monitor the treatment of depressed patients. Synthesis and characterization of an improved SERT imaging agent, ADAM (2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine)(7) was achieved. The new compound, ADAM(7), displayed an extremely potent binding affinity toward SERT ( K(i)=0.013 nM, in membrane preparations of LLC-PK(1)-cloned cell lines expressing the specific monoamine transporter). ADAM(7) also showed more than 1,000-fold selectivity for SERT over norepinephrine transporter (NET) and dopamine transporter (DAT) ( K(i)=699 and 840 nM, for NET and DAT, respectively). The radiolabeled compound [(125)I]ADAM(7) showed an excellent brain uptake in rats (1.41% dose at 2 min post intravenous [IV] injection), and consistently displayed the highest uptake (between 60-240 min post IV injection) in hypothalamus, a region with the highest density of SERT. The specific uptake of [(125)I]ADAM(7) in the hypothalamus exhibited the highest target-to-nontarget ratio ([hypothalamus - cerebellum]/cerebellum was 3.97 at 120 min post IV injection). The preliminary imaging study of [(123)I]ADAM in the brain of a baboon by single photon emission computed tomography (SPECT) at 180-240 min post IV injection indicated a specific uptake in midbrain region rich in SERT. These data suggest that the new ligand [(123)I]ADAM(7) may be useful for SPECT imaging of SERT binding sites in the human brain.

Animals↗
PubMed2000

Prognostic significance of endothelial surface score and MIB-1 labeling index in glioblastoma.

The aim of this study is to investigate the usefulness of a vascular endothelial surface score (VESS) and MIB-1 labeling index (MIB-1 LI), in a defined series of glioblastomas, as biological markers with prognostic significance of survival. Tumor tissue and survival were studied in a series of 38 patients with glioblastoma, previously treated by surgical resection and radiotherapy. For each tumor, immunohistochemical and morphometric studies were performed in order to study MIB-1 LI, and VESS, expressed as the CD-34 immunostained endothelial surface per 1000 tumor cells. The survival for the entire patient population of the series was 48.1+/-14.1 weeks, and the mean VESS for the tumors of the series ranged from 16.7 to 107 microm2 per 1000 tumor cells (mean: 38.7+/-18.2). Factors such as age or MIB-1 LI were not significatively associated with survival, but the median survival for the 18 patients with a VESS less than 35 was 50.7+/-3.7 weeks, versus 45.9+/-2.8 weeks for the 20 patients showing a VESS higher than 36 (p < 0.05). Our present results suggest that tumor VESS, expressed as the CD-34 immunostained endothelial surface per each 1000 tumor cells, may have usefulness, as angiogenic-related factor influencing survival, in patients with glioblastoma.

Adult↗
PubMed2000

Expression of vascular permeability factor in glioblastoma specimens: correlation with tumor vascular endothelial surface and peritumoral edema.

Keeping in mind that the expression of vascular permeability factor (VPF) in astrocytic tumors has been related to tumor angiogenesis and peritumoral edema (PE), the aim of this study is to investigate the correlation between degree of VPF expression by tumor cells, and degree of PE and vascular endothelial surface (VES) in glioblastoma. Tumor tissue and neuroimaging data were studied in a series of 38 patients with glioblastoma. For each tumor, immunohistochemical and morphometric studies were performed in order to obtain a score of VPF expression, and a VES score, expressed as the CD-34 immunostained endothelial surface per each 1000 tumor cells. These parameters were related to the degree of PE. The results show that in glioblastomas there exist a clear correlation between the tumor-cell expression of VPF and VES, but we failed to obtain a significant correlation between degree of PE and degree of VES, or between degree of VPF expression and degree of PE. Our present results suggest that in glioblastomas, tumor angiogenesis is clearly related to the expression of VPF by tumor cells, but factors other than intratumoralpresence of VPF may contribute to the development of PE.

Adult↗
PubMed2000

Long-term changes in dentoskeletal pattern in a case with Beckwith-Wiedemann syndrome following tongue reduction and orthodontic treatment.

Long-term changes in the dentoskeletal pattern in a 6-year-old Japanese girl with Beckwith-Wiedemann syndrome were demonstrated. The patient showed macroglossia, which is the most common symptom of the syndrome, protruded lower lip, mandibular protrusion and anterior open bite. The jaw base relationship improved to skeletal Class I and the molar relationship to Angle Class I at the early preadolescent period following tongue reduction and phase I orthodontic treatment using a chin cap and tongue crib. Optimum intercuspation of teeth was achieved after edgewise treatment without orthognathic surgery, and a skeletal Class I apical base relationship and good facial profile were maintained after the retention period of 2 years. This case report suggests that early orthodontic treatment with tongue reduction can be effective in a case with Beckwith-Wiedemann syndrome to improve an abnormal dentoskeletal pattern.

Age Factors↗